Effects of Blood-Processing Protocols on Cell-free DNA Quantification in Plasma

[摘要] Recently, qualitative analysis of cell-free DNA in blood plasma has attracted much interest for the diagnosis of cancer, fetal gender, Rhesus D status, and inherited disorders (1)(2). Other studies have shown that quantification of total plasma DNA may indicate fetal chromosomal aneuploidies and pregnancy-associated complications or the presence/recurrence of cancer (1)(3)(4). Irrespective of the type of study (qualitative or quantitative DNA analysis), it is important that cell-free plasma DNA is not contaminated with cellular DNA that interferes with analysis and accurate quantification.To prevent cellular DNA contamination, Chiu et al. (5) emphasized the need of preanalytical standardization of blood-processing protocols. The authors note that after centrifugation of blood at a low speed (800g), the amount of isolated DNA from plasma is affected by the presence of cells that remain in the plasma fraction. An additional centrifugation step (16 000g) or filtering of the plasma is necessary to produce absolutely cell-free plasma DNA. Because most laboratories, including ours, centrifuge blood at relatively low speeds (800–1500g) and store plasma without additional treatment, these results may have a serious impact on the usefulness of previously collected plasma samples for retrospective DNA analysis/quantification.To confirm the results of Chiu et al. (5), we collected EDTA blood in 7-mL Vacutainer Tubes from 18 healthy …

[学科分类] 过敏症与临床免疫学